Fundamental studies of the metallurgical, electrical, and optical properties of gallium phosphide Quarterly progress report, Apr. 1 - Jun. 30, 1966

Studies of metallurgical, electrical, and optical properties of gallium phosphid

Fundamental studies of the metallurgical, electrical, and optical properties of gallium phosphide Quarterly progress report, 1 Apr. - 30 Jun. 1969

Barrier diodes formed by nickel evaporation on undoped gallium phosphide by vertical liquid epitax

Fundamental studies of the metallurgical, electrical, and optical properties of gallium phosphide Quarterly progress report, 1 Jul. - 30 Sep. 1968

Schottky barrier diode performance tests, Be doping of GaP, and S, Se, and Te diffusion into GaA

Fundamental studies of the metallurgical, electrical, and optical properties of gallium phosphide Quarterly progress report, 1 Jan. - 31 Mar. 1968

Metallurgical, electrical, and optical properties of gallium phosphide crystal

Fundamental studies of the metallurgical, electrical and optical properties of gallium arsenide Quarterly progress report, 1 Oct. - 31 Dec. 1969

Melting points of GaP-metal systems and growth of GaP by vertical liquid epitax

Postbuckling behaviour of beams with discrete nonlinear restraints

A beam with nonlinearly ‐ elastic lateral restraints attached at discrete points along its span is investigated via analytical and numerical methods. Previous results for the critical moment and the deflected shape based on an eigenvalue analysis of a similar beam with linearly ‐ elastic restraints are discussed, along with a validation of these results against an equivalent finite element model and results from numerical continuation. A beam with nonlinearly ‐ elastic restraints is then analysed with treatments for both quadratic and cubic restraint force–displacement relationships being provided. After formulation of the potential energy functionals, the governing differential equations of the system are derived via the calculus of variations and appropriate boundary conditions are applied. The equations are then solved using the numerical continuation software AUTO ‐ 07p for a standard I ‐ section beam. The variation in elastic critical buckling moment with the linear component of the restraint stiffness is tracked via a two ‐ parameter numerical continuation, allowing determination of the stiffness values at which the critical buckling modes changes qualitatively. Using these stiffness values, subsequent analyses are conducted to examine the influence of the nonlinear component of the restraint stiffness, from which post ‐ buckling equilibrium paths and deformation modes are extracted. The results of these analyses are then compared with an equivalent Rayleigh–Ritz formulation whereby the displacement components are represented by Fourier series. Equilibrium equations are derived by minimizing the potential energy functional with respect to the amplitudes of the constituent harmonics of the Fourier series. The amplitudes are solved for in the post ‐ buckling range by AUTO ‐ O7p and equilibrium paths are produced and compared to the equivalent solutions of the differential equations, with good agreement observed

Development of a noise annoyance sensitivity scale

Examining the problem of noise pollution from the psychological rather than the engineering view, a test of human sensitivity to noise was developed against the criterion of noise annoyance. Test development evolved from a previous study in which biographical, attitudinal, and personality data was collected on a sample of 166 subjects drawn from the adult community of Raleigh. Analysis revealed that only a small subset of the data collected was predictive of noise annoyance. Item analysis yielded 74 predictive items that composed the preliminary noise sensitivity test. This was administered to a sample of 80 adults who later rate the annoyance value of six sounds (equated in terms of peak sound pressure level) presented in a simulated home, living-room environment. A predictive model involving 20 test items was developed using multiple regression techniques, and an item weighting scheme was evaluated

Propellant slosh coupling with bending Interim report

Vibrational characteristics of large liquid propellant space vehicl

SPAR improved structure/fluid dynamic analysis capability

The capability of analyzing a coupled dynamic system of flowing fluid and elastic structure was added to the SPAR computer code. A method, developed and adopted for use in SPAR utilizes the existing assumed stress hybrid plan element in SPAR. An operational mode was incorporated in SPAR which provides the capability for analyzing the flaw of a two dimensional, incompressible, viscous fluid within rigid boundaries. Equations were developed to provide for the eventual analysis of the interaction of such fluids with an elastic solid